https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96015
--- Comment #2 from Sergei Trofimovich <slyfox at inbox dot ru> --- Happens both on gcc-10.1.0 and gcc from main development branch. Here is the example of -O1/-O2 difference: $ hppa2.0-unknown-linux-gnu-gcc -lm -Wsign-compare -Wall -fno-PIE -no-pie -fno-stack-protector -O1 bug_test.c -o good-bug $ hppa2.0-unknown-linux-gnu-gcc -lm -Wsign-compare -Wall -fno-PIE -no-pie -fno-stack-protector -O2 bug_test.c -o bad-bug $ ./good-bug long_richcompare(2, 1, EQ) = FALSE (expect FALSE) $ ./bad-bug long_richcompare(2, 1, EQ) = TRUE (expect FALSE) GCC was built as: $ hppa2.0-unknown-linux-gnu-gcc -v Reading specs from /home/slyfox/dev/git/gcc-hppa2.0/gcc/specs COLLECT_GCC=/home/slyfox/dev/git/gcc-hppa2.0/gcc/xgcc COLLECT_LTO_WRAPPER=/home/slyfox/dev/git/gcc-hppa2.0/gcc/lto-wrapper Target: hppa2.0-unknown-linux-gnu Configured with: ../gcc/configure --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=hppa2.0-unknown-linux-gnu --prefix=/home/slyfox/dev/git/gcc-hppa2.0/../gcc-hppa2.0-installed --with-sysroot=/usr/hppa2.0-unknown-linux-gnu --disable-bootstrap --enable-languages=c --disable-nls CFLAGS='-O2 -g' CXXFLAGS='-O2 -g' Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 11.0.0 20200701 (experimental) (GCC)
